Killen's Pond State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Killen's Pond State Park clear sky chart from 2005-11-06 to 2025-12-03.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	14% 6% 2 6% 4 4 4 4 6% 8% 42%	126943
	Night	14% 7% 2 6% 4 4 4 3 5% 7% 44%	123762
Transparency	Day	38% 6% 12% 24% 17% 3	130503
	Night	39% 5% 12% 23% 18% 4	128259
Seeing	Day	17% 11% 27% 26% 15% 5%	16478
	Night	17% 9% 30% 31% 12% 1	25837

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 5% 2 4 3 3 3 3 5% 5% 53%	3597
	11th to 20th	Day	14% 7% 3 7% 5% 3 4 2 3 4 47%	3874
	21st to end	Day	15% 7% 2 6% 4 4 4 3 5% 5% 44%	4466
February	1st to 10th	Day	14% 7% 2 6% 4 5% 4 4 6% 7% 40%	1800
	11th to 20th	Day	17% 7% 2 6% 4 3 4 4 4 6% 43%	1912
	21st to end	Day	16% 9% 3 6% 4 3 4 3 5% 6% 41%	1650
March	1st to 10th	Day	19% 6% 1 4 3 3 3 3 4 6% 46%	4561
	11th to 20th	Day	10% 8% 2 5% 3 3 4 3 5% 6% 50%	4980
	21st to end	Day	16% 7% 2 6% 4 4 4 3 5% 6% 43%	5754
April	1st to 10th	Day	13% 8% 2 5% 4 4 4 4 6% 7% 43%	2400
	11th to 20th	Day	12% 6% 2 5% 4 4 4 4 6% 7% 46%	2374
	21st to end	Day	14% 6% 2 5% 4 4 4 4 6% 8% 44%	2400
May	1st to 10th	Day	20% 8% 3 7% 4 4 4 4 6% 8% 33%	5581
	11th to 20th	Day	22% 8% 3 6% 4 4 4 4 6% 8% 33%	6318
	21st to end	Day	17% 5% 2 6% 4 4 5% 4 6% 9% 38%	6934
June	1st to 10th	Day	11% 5% 2 6% 4 5% 5% 4 8% 9% 41%	2800
	11th to 20th	Day	11% 5% 2 5% 5% 5% 5% 4 6% 9% 43%	2800
	21st to end	Day	10% 4 2 5% 4 5% 5% 5% 8% 11% 43%	2800
July	1st to 10th	Day	7% 5% 1 6% 5% 5% 6% 5% 8% 11% 41%	6360
	11th to 20th	Day	10% 6% 2 7% 5% 6% 7% 6% 9% 12% 31%	6360
	21st to end	Day	8% 5% 2 7% 5% 5% 6% 5% 7% 10% 40%	6611
August	1st to 10th	Day	16% 6% 2 6% 4 4 5% 5% 8% 11% 33%	4212
	11th to 20th	Day	9% 5% 3 7% 4 5% 6% 5% 7% 10% 41%	3850
	21st to end	Day	8% 5% 2 6% 4 5% 5% 4 6% 9% 47%	4312
September	1st to 10th	Day	14% 5% 2 5% 4 5% 5% 4 6% 8% 44%	2400
	11th to 20th	Day	12% 6% 2 5% 4 4 4 4 5% 7% 47%	2380
	21st to end	Day	18% 8% 2 7% 4 4 4 4 4 7% 37%	2185
October	1st to 10th	Day	16% 5% 2 6% 4 3 4 3 5% 6% 47%	2000
	11th to 20th	Day	17% 5% 2 4 3 3 3 3 4 6% 51%	2000
	21st to end	Day	14% 6% 2 6% 4 3 3 3 4 6% 50%	2178
November	1st to 10th	Day	12% 5% 2 4 3 3 5% 3 5% 7% 52%	1851
	11th to 20th	Day	13% 5% 1 5% 4 3 4 4 6% 6% 50%	1890
	21st to end	Day	14% 5% 3 6% 4 3 4 3 4 6% 48%	1787
December	1st to 10th	Day	11% 5% 2 6% 4 3 4 3 5% 7% 50%	2616
	11th to 20th	Day	18% 9% 3 5% 3 3 2 3 4 6% 44%	2990
	21st to end	Day	13% 7% 2 6% 4 4 4 3 5% 8% 45%	3960
January	1st to 10th	Night	13% 7% 3 5% 4 3 4 3 4 5% 49%	6349
	11th to 20th	Night	14% 6% 2 4 3 3 3 3 4 5% 52%	6070
	21st to end	Night	15% 8% 3 6% 3 3 4 3 5% 5% 46%	6490
February	1st to 10th	Night	17% 7% 2 5% 4 4 4 4 4 6% 42%	2600
	11th to 20th	Night	19% 8% 2 6% 3 3 4 3 4 5% 43%	2373
	21st to end	Night	17% 7% 2 5% 4 4 4 3 6% 5% 44%	1980
March	1st to 10th	Night	16% 8% 2 5% 4 4 3 3 4 5% 47%	5287
	11th to 20th	Night	11% 8% 2 5% 3 4 4 3 5% 7% 48%	4980
	21st to end	Night	15% 8% 3 6% 4 4 3 3 4 5% 45%	5176
April	1st to 10th	Night	16% 8% 2 6% 4 4 3 3 4 8% 41%	2000
	11th to 20th	Night	13% 6% 2 7% 4 5% 4 4 5% 5% 45%	1975
	21st to end	Night	16% 5% 2 5% 4 4 5% 3 5% 7% 44%	2000
May	1st to 10th	Night	16% 9% 3 8% 4 5% 5% 4 6% 9% 31%	4336
	11th to 20th	Night	20% 9% 3 6% 4 4 5% 4 6% 8% 32%	3579
	21st to end	Night	18% 7% 3 5% 4 4 4 4 5% 8% 37%	3920
June	1st to 10th	Night	12% 6% 3 5% 5% 4 4 4 7% 8% 43%	1600
	11th to 20th	Night	10% 5% 2 8% 5% 4 5% 5% 6% 10% 40%	1600
	21st to end	Night	9% 5% 2 6% 5% 5% 6% 4 8% 10% 41%	1600
July	1st to 10th	Night	8% 6% 3 7% 5% 5% 5% 5% 7% 10% 38%	3598
	11th to 20th	Night	10% 7% 3 8% 6% 5% 5% 4 7% 12% 33%	3597
	21st to end	Night	9% 6% 2 6% 5% 5% 5% 4 7% 9% 41%	4236
August	1st to 10th	Night	16% 7% 3 7% 4 4 5% 4 6% 11% 32%	2915
	11th to 20th	Night	10% 6% 3 7% 5% 4 5% 4 7% 8% 40%	3188
	21st to end	Night	8% 6% 2 5% 4 4 4 4 6% 8% 51%	3586
September	1st to 10th	Night	14% 6% 2 6% 5% 4 3 3 5% 7% 46%	2000
	11th to 20th	Night	10% 6% 2 5% 3 2 3 3 6% 8% 51%	2020
	21st to end	Night	20% 7% 2 5% 3 5% 4 4 6% 6% 38%	2210
October	1st to 10th	Night	15% 7% 3 6% 3 3 3 3 4 6% 47%	2400
	11th to 20th	Night	17% 5% 1 4 3 3 3 2 4 5% 52%	2400
	21st to end	Night	14% 7% 2 5% 3 3 3 4 4 6% 49%	2660
November	1st to 10th	Night	10% 6% 1 5% 4 3 4 3 5% 5% 53%	2667
	11th to 20th	Night	14% 7% 3 5% 3 4 4 3 4 5% 49%	2730
	21st to end	Night	12% 6% 2 4 4 4 4 4 6% 7% 48%	2830
December	1st to 10th	Night	11% 6% 2 4 3 3 4 3 5% 7% 52%	4609
	11th to 20th	Night	21% 6% 2 5% 4 3 4 3 5% 8% 39%	5205
	21st to end	Night	14% 8% 3 7% 4 4 4 3 5% 7% 41%	6996

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	32% 4 7% 27% 26% 4	3598
	11th to 20th	Day	42% 4 8% 22% 18% 7%	3874
	21st to end	Day	42% 4 10% 28% 14% 3	4466
February	1st to 10th	Day	41% 6% 14% 25% 13% 2	1800
	11th to 20th	Day	42% 4 10% 24% 17% 3	1921
	21st to end	Day	44% 4 11% 21% 16% 4	1650
March	1st to 10th	Day	38% 4 8% 23% 19% 7%	4561
	11th to 20th	Day	34% 5% 8% 27% 20% 6%	4980
	21st to end	Day	43% 4 9% 18% 21% 7%	5754
April	1st to 10th	Day	38% 6% 13% 21% 16% 6%	2400
	11th to 20th	Day	35% 6% 11% 23% 18% 6%	2374
	21st to end	Day	37% 6% 13% 21% 19% 4	2400
May	1st to 10th	Day	47% 7% 16% 17% 11% 2	5613
	11th to 20th	Day	48% 7% 11% 23% 10% 1	6322
	21st to end	Day	42% 6% 12% 23% 16% 1	6949
June	1st to 10th	Day	37% 8% 15% 23% 16% 2	2800
	11th to 20th	Day	36% 8% 14% 23% 15% 3	2800
	21st to end	Day	32% 9% 15% 25% 19% 1	2800
July	1st to 10th	Day	35% 10% 20% 20% 13% 2	6290
	11th to 20th	Day	42% 10% 21% 21% 6% 1	6285
	21st to end	Day	36% 9% 12% 23% 19% 1	6422
August	1st to 10th	Day	42% 7% 18% 25% 8%	4199
	11th to 20th	Day	37% 8% 14% 29% 12% 1	3886
	21st to end	Day	32% 7% 13% 28% 18% 3	4312
September	1st to 10th	Day	38% 7% 13% 20% 19% 3	2400
	11th to 20th	Day	35% 5% 11% 25% 22% 2	2380
	21st to end	Day	47% 5% 9% 19% 17% 3	2185
October	1st to 10th	Day	32% 5% 9% 21% 27% 5%	3260
	11th to 20th	Day	25% 3 6% 27% 28% 10%	3240
	21st to end	Day	24% 3 9% 31% 26% 8%	3492
November	1st to 10th	Day	32% 5% 11% 29% 19% 4	1851
	11th to 20th	Day	35% 5% 10% 23% 23% 3	1890
	21st to end	Day	37% 4 10% 30% 17% 3	1787
December	1st to 10th	Day	34% 4 18% 25% 15% 4	2616
	11th to 20th	Day	42% 4 12% 27% 11% 3	2986
	21st to end	Day	37% 5% 16% 23% 19% 1	3960
January	1st to 10th	Night	37% 4 7% 23% 24% 5%	6349
	11th to 20th	Night	35% 3 8% 26% 20% 7%	6070
	21st to end	Night	40% 3 9% 28% 18% 2	6490
February	1st to 10th	Night	43% 4 13% 24% 14% 2	2600
	11th to 20th	Night	44% 4 8% 21% 19% 5%	2375
	21st to end	Night	41% 4 10% 22% 18% 5%	1980
March	1st to 10th	Night	40% 3 9% 24% 14% 10%	5287
	11th to 20th	Night	36% 5% 11% 24% 18% 6%	4980
	21st to end	Night	42% 4 9% 18% 23% 5%	5176
April	1st to 10th	Night	43% 5% 10% 19% 19% 5%	2000
	11th to 20th	Night	40% 5% 11% 19% 20% 6%	1975
	21st to end	Night	39% 5% 10% 21% 19% 5%	2000
May	1st to 10th	Night	49% 6% 14% 20% 9% 2	4366
	11th to 20th	Night	50% 6% 13% 20% 10% 1	3580
	21st to end	Night	45% 6% 14% 19% 14% 2	3927
June	1st to 10th	Night	38% 7% 13% 22% 18% 2	1600
	11th to 20th	Night	37% 9% 15% 24% 13% 2	1600
	21st to end	Night	34% 8% 16% 22% 17% 3	1600
July	1st to 10th	Night	40% 8% 18% 19% 13% 2	3560
	11th to 20th	Night	43% 10% 21% 20% 5% 1	3552
	21st to end	Night	37% 8% 15% 23% 18%	4111
August	1st to 10th	Night	46% 7% 18% 20% 8%	2904
	11th to 20th	Night	38% 8% 15% 27% 12% 1	3218
	21st to end	Night	31% 6% 12% 28% 21% 2	3586
September	1st to 10th	Night	39% 5% 11% 23% 17% 4	2000
	11th to 20th	Night	31% 6% 11% 26% 22% 4	2020
	21st to end	Night	45% 6% 10% 20% 16% 3	2210
October	1st to 10th	Night	37% 5% 10% 22% 22% 4	3920
	11th to 20th	Night	24% 3 12% 22% 31% 8%	3899
	21st to end	Night	24% 3 11% 29% 26% 7%	4284
November	1st to 10th	Night	33% 4 9% 26% 21% 6%	2667
	11th to 20th	Night	38% 4 10% 22% 21% 6%	2730
	21st to end	Night	35% 4 12% 26% 20% 3	2830
December	1st to 10th	Night	32% 4 14% 28% 19% 3	4609
	11th to 20th	Night	44% 4 13% 20% 15% 4	5208
	21st to end	Night	42% 5% 13% 21% 18% 2	6996

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	23% 22% 33% 18% 5% 1	200
	11th to 20th	Day	24% 27% 31% 15% 4	260
	21st to end	Day	20% 21% 39% 14% 5% 1	330
February	1st to 10th	Day	21% 23% 36% 16% 4	300
	11th to 20th	Day	28% 21% 38% 11% 2	460
	21st to end	Day	22% 20% 36% 17% 4	414
March	1st to 10th	Day	21% 22% 31% 21% 4	500
	11th to 20th	Day	20% 22% 33% 18% 5% 2	500
	21st to end	Day	23% 16% 34% 21% 5% 1	550
April	1st to 10th	Day	20% 20% 37% 16% 4 2	500
	11th to 20th	Day	16% 16% 34% 23% 10% 1	492
	21st to end	Day	21% 13% 32% 23% 10% 1	500
May	1st to 10th	Day	22% 14% 33% 21% 7% 3	503
	11th to 20th	Day	19% 11% 32% 27% 11% 1	527
	21st to end	Day	18% 6% 24% 27% 19% 6%	573
June	1st to 10th	Day	13% 6% 27% 30% 19% 5%	530
	11th to 20th	Day	14% 5% 25% 33% 17% 7%	530
	21st to end	Day	11% 3 19% 36% 24% 6%	530
July	1st to 10th	Day	9% 3 15% 36% 26% 11%	525
	11th to 20th	Day	4 3 15% 37% 32% 10%	524
	21st to end	Day	9% 3 17% 34% 27% 9%	576
August	1st to 10th	Day	13% 3 17% 33% 25% 10%	526
	11th to 20th	Day	11% 3 16% 29% 32% 10%	519
	21st to end	Day	9% 4 16% 33% 25% 13%	583
September	1st to 10th	Day	15% 5% 20% 28% 19% 12%	530
	11th to 20th	Day	12% 6% 20% 28% 25% 10%	530
	21st to end	Day	24% 7% 23% 29% 12% 5%	530
October	1st to 10th	Day	18% 6% 23% 27% 17% 10%	530
	11th to 20th	Day	18% 11% 25% 24% 17% 5%	530
	21st to end	Day	16% 11% 32% 27% 10% 4	570
November	1st to 10th	Day	15% 13% 31% 24% 13% 4	425
	11th to 20th	Day	17% 18% 32% 23% 10% 1	430
	21st to end	Day	16% 20% 28% 25% 11% 1	327
December	1st to 10th	Day	15% 20% 39% 21% 4 1	204
	11th to 20th	Day	27% 17% 33% 18% 6%	200
	21st to end	Day	20% 17% 29% 25% 8%	220
January	1st to 10th	Night	18% 19% 38% 21% 4	800
	11th to 20th	Night	21% 15% 34% 25% 4	800
	21st to end	Night	18% 15% 41% 24% 3	880
February	1st to 10th	Night	20% 13% 39% 26% 3	800
	11th to 20th	Night	25% 18% 37% 20% 1	783
	21st to end	Night	21% 18% 36% 22% 3	660
March	1st to 10th	Night	19% 14% 40% 23% 4	800
	11th to 20th	Night	20% 15% 37% 21% 7% 1	800
	21st to end	Night	21% 9% 41% 23% 5%	880
April	1st to 10th	Night	21% 14% 41% 19% 5%	800
	11th to 20th	Night	14% 11% 35% 34% 6%	791
	21st to end	Night	18% 9% 35% 30% 8%	800
May	1st to 10th	Night	19% 8% 34% 30% 9%	737
	11th to 20th	Night	17% 5% 33% 36% 9% 1	398
	21st to end	Night	14% 4 22% 39% 19% 2	433
June	1st to 10th	Night	14% 3 24% 43% 16% 1	400
	11th to 20th	Night	10% 2 24% 44% 19% 1	400
	21st to end	Night	11% 2 20% 50% 17% 1	400
July	1st to 10th	Night	10% 3 17% 45% 23% 1	390
	11th to 20th	Night	6% 2 12% 46% 31% 2	388
	21st to end	Night	6% 2 16% 44% 29% 2	570
August	1st to 10th	Night	11% 2 12% 47% 27% 2	597
	11th to 20th	Night	12% 3 13% 41% 29% 3	781
	21st to end	Night	12% 3 14% 39% 28% 4	880
September	1st to 10th	Night	17% 2 16% 38% 23% 4	800
	11th to 20th	Night	13% 2 15% 38% 28% 4	800
	21st to end	Night	23% 4 19% 34% 18% 1	800
October	1st to 10th	Night	19% 4 20% 31% 21% 5%	800
	11th to 20th	Night	20% 8% 26% 30% 16% 1	800
	21st to end	Night	17% 8% 33% 29% 12% 1	880
November	1st to 10th	Night	14% 8% 33% 30% 13% 2	820
	11th to 20th	Night	18% 13% 32% 28% 8%	840
	21st to end	Night	13% 14% 35% 28% 9% 1	840
December	1st to 10th	Night	22% 13% 34% 21% 9% 1	809
	11th to 20th	Night	19% 12% 37% 26% 6%	800
	21st to end	Night	18% 12% 37% 30% 4	880

Page generated at 2025-11-30 01:00:50. Version ac07

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